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Why this status?
Click here for detailed information on water quality monitoring
The scienceSummer season monitoring
LAWA shows the best available water quality information to help you decide where to swim.
Special Status
Unsuitable for swimming.
This site has temporarily been determined as unsuitable for swimming, and we recommend people do not swim at this site.A health warning has been issued by the local Medical Officer of Health for Lake Rotorua due to a potentially toxic algal bloom. During the warmer months lakes and rivers can be affected by blooms of blue-green algae which can lead to a release of toxins into the water.
“These algal blooms can readily move from one part of the lake to another. The algae can also quickly multiply to dangerous levels and lake users need to be vigilant before having any contact with the lake water,” says Dr Phil Shoemack, Te Whatu Ora Medical Officer of Health for Toi Te Ora Public Health.
“Algal blooms can sometimes produce toxins that are harmful for people as well as animals. It is best to avoid contact with the water if it looks discoloured, has an unusual smell, has green or brown particles suspended in it, or if you can see scum or leathery mats of algae on the surface or on the bottom of the waterway,” says Dr Shoemack.
“These blooms have the capacity to release toxins into the water which can cause significant ill-health to anyone who has contact with the water. The toxins can affect the nervous system causing numbness and difficulty with breathing, and also sparking asthma attacks. Contact with the water can also cause skin rashes, stomach upsets and visual problems,” says Dr Shoemack.
Lakes are typically dominated by free-floating algal blooms, while rivers are more prone to algal blooms that grow in mats attached to rocks at the bottom. They can also build up at the shoreline.
“Algal mats and scum may also accumulate along the edges of lakes or rivers so it’s especially important that parents ensure that children avoid contact with these as they may be toxic,” says Dr Shoemack. You should seek medical advice from your GP if you become unwell after having contact with the recreational water.
Dogs are also particularly at risk of serious illness if they consume or have contact with toxic algae. They should be kept away from the water if it looks like there may be a bloom. They may also eat algal mats that accumulate in and around rivers.
A health warning is issued by Toi Te Ora Public Health if recreational water monitoring results provided by Regional Councils show a site to have high levels of blue-green algae.
Find information on local health warnings on the following channels:
- List of health warnings - Toi Te Ora Public Health website
- Follow Toi Te Ora social media channels at Facebook, Instagram, and X
- Signage at locations (erected by local councils)
Reminder
Heavy rain flushes contaminants from urban and rural land into waterways and we advise you not to swim for 2 – 3 days after heavy or prolonged rain – even at sites that generally have good water quality. Check that the water is clean and clear before taking a dip.
Potentially toxic algae can rapidly bloom to harmful levels, and not all freshwater sites are monitored for toxic algae. Play it safe — if you can see toxic algal blooms in rivers or lakes, avoid contact or choose another site to swim.
Summer season monitoring history
- Samples this season
- Samples from last 5 years
E. coli sampling graph- View as graph
- View as donut
Toxic Algae sampling graphWhat do the monitoring results mean?
Long-term grade information
Long-term grade based on five years of dataMinimum data points required 50 Highest E. coli per 100ml value {{riskData.maxValue | number:0}} Number of data points available {{riskData.dataPoints | number:0}} Lowest E. coli per 100ml value {{riskData.minValue | number:0}} Hazen 95th percentile result {{riskData.hazenResult}} Long-term grade {{riskData.rating}}What do the long-term grade icons mean?
95th percentile of E. coli / 100 mL is <= 130.
95th percentile of E. coli / 100 mL is > 130 and <= 260.
95th percentile of E. coli / 100 mL is > 260 and <= 540.
95th percentile of E. coli / 100 mL is > 540.Learn more
See factsheets for more information.
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What about my dog?
Information about toxic algae
Dog ownersKeeping your dog safe and healthy this summer
A trip to a lake is a lot of fun and knowing how to keep your dog safe means you are able to relax and enjoy the adventure even more. Toxic algae can be harmful to dogs (and us) – this section shows you what to look for.
What to do
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The best thing you can do to keep yourself, your kids and your dog safe is to know what toxic algae looks like and avoid it.
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If you are not sure, keep your dog on a lead at a lake and don’t let them in or near the water. Bring water from home for your dog so that they don’t need to drink out of the lake.
What is toxic algae?
Toxic algae, known scientifically as cyanobacteria, are naturally occurring in rivers and lakes in New Zealand, including waterways with good water quality. Most of the year it is present in lakes at low levels that are not much of a danger. But algae can be a problem during the summer months, when warm temperatures and nutrients in the lake create an environment where it can thrive, forming extensive blooms which can be toxic to humans, dogs, livestock and wildlife.
Scientists do not yet understand when and why this algae turns toxic, so to be safe, always treat it as toxic.
Dogs are particularly susceptible to poisoning from toxic algae as they may drink lake water or play in the water.
What to look for
Toxic algae grows within the water column in lakes and cause the water to become murky or cloudy.
These free floating algae blooms in lakes are generally green in colour and can look like paint, petrol or pea soup. It can also form foam or scum on the water’s surface, especially at the water’s edge. Sometimes blooms may not be very visible.
Council staff monitor for these mats in lakes where blooms are known to occur. Blooms can occur very suddenly (within an hour) so please alert your regional or unitary council if you notice a new algal bloom in a lake.
What if my dog has eaten toxic algae?
If you suspect that your dog has eaten toxic algae, you should contact your vet as soon as possible. Signs a dog has been poisoned by toxic algae include lethargy, muscle tremors, fast breathing, twitching, paralysis and convulsions.
Find out more about toxic algae here
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What's at this site?
Find out all recreational activities and facilities at this site
Activities & facilitiesSite suitable for these activities and has these facilities
Our lakes, rivers, and beaches are great natural playgrounds but they can be unpredictable. Be aware of other potential risks such as rips, strong currents, sudden drop offs, or underwater objects before jumping in. LAWA recommends that you avoid swimming for 2 - 3 days after heavy rainfall and follow the advice of any warning signs in place.
Activities
Facilities